Expanded polymer insulation blocks, such as insulation plates (EPS plates) or the like manufactured from expanded polystyrene are typically manufactured by expanding pre-expanded polymer beads in a standard-sized mould, in which case the pre-expanded beads expand evenly in every direction. Thus, the structure of the cells in the finished expanded polymer block is round. The round shape of the cells gives standard properties to the insulation block in every direction of the block.